Rotary kiln



G. E. SEIL ROTARY KILN Oct. 18, 1949.

Filed April 21., 1945 2 Sheets-Sheet l I I I l I 11 I N VEN TOR.

GILBERT E SEIL,

ATTORNEY Oct. 18, 1949. 5. E. SEIL 2,484,911

ROTARY KILN Filed April 21, 1945 2 Sheets-Sheet 2 INVENTOR:

GILBERT E. SEIL,

ATTORNEY Patented Oct- 18, 1949 ROTARY KILN Gilbert Edward Sell, Cynwyd, Pa.; Frances Merritt Sell, executrix of said Gilbert Edward Sci], deceased, assignor to Frances Merritt Sell Application April 21, 1945, Serial No. 589,633

2 Claims. 1

This invention relates to rotary kilns, and more particularly to the control of the place and of the character of combustion taking place in the kiln.

Heretoiore, a mixture of raw material and solid fuel, such as coke, has been supplied to the kiln at its feed end. Since, under such circumstances, there is no control of the combustion, it normally starts too early in the progress of the material through the kiln. This is not only ineflicient, but it tends to cause rings to form on the kiln lining. Moreover, it requires coke of particular characteristics, when so used.

Therefore, it is an object of this invention to control the place or zone of the combustion with respect to the length of the kiln. Another object is to be able touse cheaper grades of fuel, such as breeze, which is a by-product now difilcult to use in rotary kilns. Another object of this invention is to devise directional air streams or jets so that not only can the place of addition of the fuel be controlled, but also the place of impingement of the delivered streams of air precisely into the combustion zone for efllcient combustion therein. A further object is to devise means whereby coke can be delivered into the kiln at predetermined places so that it can not only be used as fuel, but can also be used for oxygencombining or reducing purposes, such as in the reducing of iron ore to yield metallic iron. A still further object is to arrange for the addition of reagents for chemical reaction purposes into predetermined places in the kiln. Still further objectives will appear as the specification proceeds.

The invention resides in the use Of scooping members carried by the kiln adapted to scoop up the coke or other additive for the kiln. Rotation of the kiln causes the scooped-up material to be carried up with the scoop rotating with the kiln until it reaches the zenith of rotation, whereupon it falls through an aperture or opening (hooded by the scoop) into the kiln. This arrangement may or may not be supplemented, in the concept of this invention, by the use of air-jets that are directionally controllable to deliver air into the The best embodiment of the invention now known to me is shown and described herein for illustrative purposes, but this is not to be taken as limiting, i'or obviously the invention is capable of other embodiments and especially structural modifications and rearrangements. The scope thereof is defined in the appended claims which should be read with the usual latitude for equivalents and reversal 01' parts.

The invention has been illustrated in the accompanying drawings, in which Figure 1 shows a vertical longitudinal view through a kiln in which this invention is embodied. Fig. 2 is a vertical transverse sectional view taken along the line IIII in Fig. 1. Fig. 3 is a vertical transverse view taken through the kiln showing a modification; while Fig. 4 is a partial vertical longitudinal view to show the modification of Fig. 3 from a different angle. Fig. 5 is a transverse vertical view through the kiln showing a modified form of feeding apparatus associated with the scoop means. Fig. 6 is a partial isometric view of the arrangement of Fig. 5.

In the drawings, I I indicates generally a rotary kiln, having a cylindrical casing or shell i2, and a refractory lining i3; a stationary shield ll at the discharge end, and a feed supply means I! at the opposite end. The kiln is provided with the usual tires l6 running on rollers i1, and the kiln is rotated by suitable power means which are not shown. 20 represents an aperture passing through the lining 13 and the shell I! of the kiln, which communicates with the interior of scoop means 2i providing a feed-conducting channel or curved conduit 22. The scoop is preferably, al-

though not necessarily, rectangular in cross seczone of combustion that is determined by the place tion, and it extends peripherally around the shell I'Z through slightly more than degrees. The scoop has a closed end 23 hooding the aperture 20, and an open entrance end 2!. The scoop 2| is more or less horn-shaped as shown in Figs. 2 and 3 in that the cross-sectional area at its entrance end is greater than elsewhere, and the cross-sectional area diminishes as its closed end 23 is approached. Duplicate scoop means may be used at other places on the kiln, such as indicated generally at 25.

Burner assemblies or arrangements 30 are associated with the shield ll. They preferably are of the type shown and claimed in-my Patent No. 2,137,185, patented November 15, 1938. The gist of this arrangement is that it is constructed and arranged to direct a flame onto the furnace burden or bed of material being heat-treated therein, in a manner whereby the impingement of the flame on the burden can be accurately and precisely controlled. For illustrative purposes, I have shown only one such burner in Fig. 1, although a number may be used, and I have shown a nozzle 3| passing through a ball arrangement 32 ca.- pable of angular adjustment, and the ball arrangement is adjustably held in an opening 33 in the stationary shield I4. 34 represents a conduit for conducting gas, or air, or air and fuel, to the burner, whichever is to be used therein. Dotted lines 35 indicate the predetermined zone in which the flame from the burner 3| can be controlled, especially to include a plane transverse of the kiln which corresponds to the scoop means 2|. Heattreated material is discharged through channel 26 in shield l 4.

Adjacent the aperture 20 through the kiln, the refractory casing l3 can be arranged as shown in Figs. 3 and 4, wherein the aperture 20 is surrounded on the interior of the kiln by dam means exemplified by an annular boss-like protuberance 31, and the refractory bricks 38 and 39 (for instance) adjacent thereto are stepped down from the level of the protuberance 31 down to be flush with the lining l3. This arrangement is not shown in Figs. 2 and 3, but of course could be used therein.

Material to be fed to the kiln through the scoop means 2| can be held in a pile 40 as shown in Fig. 2, or it can be held in a hopper 4|, as shown in Fig. 5, having a chute 42 whose outlet is controlled to be opened and closed by a closure or gate 43, preferably pivoted at 44, whose pivot pin has an arm 45 terminating as an enlargement such as a ball 46 adapted to slide up, along, and then drop off a curved inclined plane-shaped block il carried exteriorly of the kiln shell l2. The block 41 has a curved inclined from face 48 and a rear face 49 that is radially disposed to the shell I2.

In operation, the charge of material to be heat treated in the rotary kiln, is supplied thereto through the feeding arrangement l5. Rotation of kiln that is inclined downwardly toward the discharge end, causes the material to progress along the interior of the kiln as a bed extending from the feed end to the discharge end of the kiln. Meanwhile the material is heated by means of the burners shown generally at 30. In the preferred form, only air is supplied by this burner arrangement, while solid fuel is supplied to the kiln at a predetermined place or zone by means of the scoop 2|, but it is within the concept of this invention to use the combination of fuels-either solid or liquid or both.

As the kiln rotates, its scoop 2| rotates with it and when the open end 24 of the scoop reaches the nadir of its travel (as shown in Fig. 2), the scoop picks up a quantity of fuel from the pile 40. Continued rotation of the kiln causes the fuel so picked up to slide or be carried along in the scoop until it reaches the closed end 23. Further rotation carries the fuel in the closed end 23 up- .wardly until the aperture 20 approaches its assured by directing the impingement of the air stream or streams from the burner 30 directly onto the bed in the kiln in the zone thereof which receives the solid fuel so fed by means of the scoop 2|.

A modified method of feeding solid fuel to the kiln through the scoop 2| is shown in Figs. 5. 6 and 7, wherein, when the block. 4'I;carried exteriorly of the kiln shell l2 approaches its zenith, it engages the ball 46 on the arm 45 and the inclined face of the block causes the pivot pin 44 to rotate, whose rotation causes the closure-or gate 43 to open to deliver a charge of solid fuel into the upmoving open end 24 of the scoop 2|. Continued rotation of the kiln causes the ball 48 to drop off the radially disposed rear face 49 of the block 41 which causes the gate or closure 43 to close the chute 42 again. Continued rotation of the kiln then causes the fuel load in the scoop 2| to be delivered into the kiln through the aperture 20. If a further scoop such as 25 is used, it can operate in the same way either to feed fuel to the kiln, to feed a quantity of material to be heat-treated in the kiln, or some reagent or additive, as hereinafter described.

A further possible modification is that scoop means such as 2| or 25 may be associated with the kiln but in reverse direction, so that by its use, material can be discharged from the kiln prior to its otherwise normal exit through the discharge channel 26. That is, the scoop is so directed around the kiln with respect to rotation of the kiln, that rotation of the kiln causes material to pass from the kiln into the scoop and then out from the scoop. In other words, passage of material in the discharge scoop is just the opposite to what it is in the feed scoops 2| and 25. When a scoop is so used as a discharge means, the dam means 3! is omitted so as not to interfere with.

outflow of material from the kiln through the aperture into the scoop. By such an arrangement, portions of the charge of the kiln can be tapped off so that a determination can be made of what has taken place or the extent of heat-treatment in the kiln.

Up to the present time, it has been economically impossible to feed the fuel for combustion with a raw charge because the combustion started too early in the kiln and caused ridges or rings to build in the kiln. By using this method of feeding, it is possible to feed the fuel, whether it be coarse or fine, wet or dry, liquid or solid, into the kiln at a predetermined place. By regulating the impingement of the air on the bed, it is possible to take care of the recovered heat by preheating the air, and it is also possible to control the zone of combustion so that the heat is lib! led at a. predetermined place.

In Fig. 1 the distance A may be 25 feet if it is desired to have the combustion take place in a zone 13 feet to 6 feet from the end of the kiln. If, on the other hand, it is desired to have the combustion take place earlier, the distance B, which may be 25 feet plus any desired number, may be used. If a reagent is desired, such as lime, in the nodulizing of iron ore, it may be added at point C which may be any desired distance from the ends of the kiln.

In feeding a rotary kiln it is quite often difllcuit to feed as large a charge as is desired because of the spill-over at the back end of the kiln. Any charging device which has been used up to the present time interferes with the flow of the products of combustion out of the kiln and, therefore, requires a relatively high stack or a large 5 J fan to remove the products of combustion. By using this same idea in feeding the kiln, it is possible to feed 10 feet or 15 feet, or any desired distance from the entrance end of the kiln in such a way that the back flow of the feed will never leave the kiln.

Another advantage in this method is that by using larger percentages of fuel than that necessary for combustion. it is possible to reduce the iron ore to metallic iron which may be discharged from the ldln as a liquid.

Iclaim:

1. Rotary kiln apparatus having a cylindrical kiln provided with a casing and a refractory lining, means for feeding material to be heattreated therein at one end thereof, means for discharging material at the other end thereof, means for rotating the kiln; and means for delivering solids material into the kiln through its casing during rotation of the kiln comprising an aperture through the kiln, channel means connected with the aperture disposed exteriorly of the kiln and having one open end through which solid fuel may be supplied to the kiln at a predetermined place between the ends thereof; and a second aperture through the kiln as well as another channel means disposed exteriorly of the 6 kiln and having one open end through which a solid chemical reagent may be supplied to the kiln at a predetermined place between the place of the feed of solid fuel and one end of the kiln. 2. Apparatus according to claim 1, with the addition of means for controllably directing air Jets into the kiln, and means for controllably directing flames onto the burden of the kiln. with the location of said apertures being at any strategic point along the casing of the kiln.

GILBERT EDWARD BEIL.

REFERENCES CITED The following references are of record in the' file of this patent:

UNITED STATES PATENTS Great Britain Oct. 10, 1911 

